Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
cupid_pub:the_cupid_experiment [2021/05/22 14:19] – [The Experiment] benatocupid_pub:the_cupid_experiment [2021/06/04 08:31] (current) – [The Experiment] benato
Line 44: Line 44:
  
 |{{ cupid_pub:double_beta.png?330 }} |{{ cupid_pub:screenshot_20210522_144702.jpeg?330 }}| |{{ cupid_pub:double_beta.png?330 }} |{{ cupid_pub:screenshot_20210522_144702.jpeg?330 }}|
-|Decay scheme of 2νββ (top) and 0νββ decay (bottom). The two processes share the same parent and daughter nucleus, but differ for the number of emitted partiles, and consequently their energy.|The measurable sum electron spectrum is a continuum for 2νββ decay, and an excess at Q<sub>ββ</sub> for 0νββ decay.|+|Decay scheme of 2νββ (top) and 0νββ decay (bottom). The two processes share the same parent and daughter nucleus, but differ for the number of emitted particles, and consequently their energy.|The measurable sum electron spectrum is a continuum for 2νββ decay, and an excess at Q<sub>ββ</sub> for 0νββ decay.|
  
  
Line 65: Line 65:
 Thus, CUPID will not only change the crystal, but also the candidate isotope. The reason for this choice is twofold: Thus, CUPID will not only change the crystal, but also the candidate isotope. The reason for this choice is twofold:
 on the one hand, Li<sub>2 </sub>MoO<sub>4</sub> is a scintillating material with a particle-dependent light yield, on the one hand, Li<sub>2 </sub>MoO<sub>4</sub> is a scintillating material with a particle-dependent light yield,
-on the other hand the candidate isotpe <sup>100</sup>Mo has a Q-value of 3034 keV +on the other hand the candidate isotope <sup>100</sup>Mo has a Q-value of 3034 keV 
-(compared to 2527 keV of <sup>130</sup>Te), which lies above most of the γ background from environmental radioactivity. +(compared to 2527 keV of <sup>130</sup>Te), which lies above most of the γ background from environmental radioactivity. Special attention is paid to the minimization of the radioactive contamination levels of all employed materials. Using the information from the predecessor experiments CUORE, [[https://cupid-0.lngs.infn.it/|CUPID-0]], and [[https://cupid-mo.mit.edu|CUPID-Mo]], the projected background at Q<sub>ββ</sub> is expected to be at the level of 10<sup>-4</sup> counts/keV/kg/yr. 
- +CUPID-Mo  has  robustly  demonstrated  that Li<sub>2</sub>MoO<sub>4</sub> scintillating bolometers 
 +meet the requirement for CUPID. CUPID-Mo was an array of 20 elements that took data until 2020 in the Modane underground laboratory in France, as a follow-up  of  the LUMINEU  project. 
 +It  has shown  the  maturity  reached  by  the proposed CUPID  technology  and  the  high  standard  of the Li<sub>2</sub>MoO<sub>4</sub> detectors  in  terms  of  energy resolution, α/β rejection capabilities, internal radiopurity, and overall reproducibility of the results.
  
  
Line 75: Line 76:
  
  
-==== The Detector ==== +===== The Detector =====
- +
- +
-The CUPID crystals are operated as cryogenic calorimeters, each equipped with a cryogenic light detector. A particle interaction in the crystal produces a phonon  and light signal (see figure below), the latter one is used to discriminate  α background from the electrons events.  +
-{{ :cupid_pub:cupid_detector.png?450 |}} +
- +
- +
- +
- +
- +
- +
- +
- +
- +
- +
- +
- +
  
 +In CUPID, the Li<sub>2</sub>MoO<sub>4</sub> crystals are operated as cryogenic calorimeters, and coupled to a light detector. The light detectors are germanium wafers, and are also instrumented as calorimeters.
 +A particle interaction in the crystal produces phonons and scintillation light.
 +The heat from recombining phonons is read by a Neutron Transmutation Doped (NTD) germanium thermistor
 +glued to the crystal. The light escapes the crystal, inducing a phonon signal in the light detector, which is also read by an NTD.
  
 +|{{ cupid_pub:cupid_detector.png?350 }}|{{cupid_pub:screenshot_20210522_221509.jpeg?450}}|
 +|Schematic of a cryogenic calorimeter, with the heat channel (blue) and a light detector (gray).|Installation of crystals for a CUPID test run. A light detector is visible in the bottom right.|